Recent advances in molecular and cell biology have taken place as a result of the development of rapid and efficient analytical techniques. Due to miniaturization and multiplexing techniques like gene chip or biochip enable the characterization of complete genomes in a single experimental setup. PCR is a molecular biology method for the in-vivo amplification of nuclear acid molecules. The PCR technique is rapidly replacing other time consuming and less sensitive techniques for identification of biological species and pathogens in forensic, environmental, clinical and industrial samples. Among the biotechniques, PCR has become the most important analytical step in life sciences laboratories for a large number of molecular and clinical diagnostics. Important developments made in PCR technology like real-time PCR, have led to rapid reaction processes compared to conventional methods. During the past several years, microfabrication technology has been expanded to the miniaturization of the reaction and analysis system such as PCR analysis with the intention of further reducing analysis time and consumption of reagents. Several research groups have been working on the ‘lab-on-a-chip’ devices and have led to number of advances in the fields of miniaturized separation and reaction systems.
In most PCR's available now, instantaneous temperature changes are not possible because of sample, container, and cycler heat capacities, and extended amplification times of 2 to 6 hours result. During the periods when sample temperature is making a transition from one temperature to another, extraneous, undesirable reactions occur that consume important reagents and create unwanted interfering compounds.